/*    $OpenBSD: fseek.c,v 1.7 2005/08/08 08:05:36 espie Exp $ */
/************************************************************************
 * Copyright (c) 1990, 1993
 *    The Regents of the University of California.  All rights reserved.
 * Copyright (c) <2014-2015>, <Huawei Technologies Co., Ltd>
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Chris Torek.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 ************************************************************************/

/************************************************************************
 * Notice of Export Control Law
 * ===============================================
 * Huawei LiteOS may be subject to applicable export control laws and regulations,
 * which might include those applicable to Huawei LiteOS of U.S. and the country
 * in which you are located.
 * Import, export and usage of Huawei LiteOS in any manner by you shall be in
 * compliance with such applicable export control laws and regulations.
 ************************************************************************/

//#include <sys/types.h>
#include "sys/stat.h"
#include "fcntl.h"
#include "stdio.h"
#include "stdlib.h"
#include "errno.h"
#include "local.h"
#ifdef LOSCFG_LLTSER
#include "gcov_ser.h"
#endif

#define    POS_ERR    (-(fpos_t)1)

#define _offset _unused_0
#define __SOFF  0x1000      /* set iff _offset is in fact correct */

/*
 * Seek the given file to the given offset.
 * `Whence' must be one of the three SEEK_* macros.
 */
int
fseeko(FILE *fp, off_t offset, int whence)
{
    fpos_t (*seekfn)(void *, fpos_t, int);
    fpos_t target, curoff;
    size_t n;
    struct stat st;
    int havepos;

    /* make sure stdio is set up */
    if (!__sdidinit_flag)
        __sinit();

    /*
     * Have to be able to seek.
     */
    if ((seekfn = fp->_seek) == NULL) {
        errno = ESPIPE;            /* historic practice */
        return (EOF);
    }

    /*
     * Change any SEEK_CUR to SEEK_SET, and check `whence' argument.
     * After this, whence is either SEEK_SET or SEEK_END.
     */
    FLOCKFILE(fp);
    switch (whence) {

    case SEEK_CUR:
        /*
         * In order to seek relative to the current stream offset,
         * we have to first find the current stream offset a la
         * ftell (see ftell for details).
         */
        (void)__sflush(fp);    /* may adjust seek offset on append stream */
        if (fp->_flags & __SOFF)
            curoff = fp->_offset;
        else {
            curoff = (*seekfn)(fp->_cookie, (fpos_t)0, SEEK_CUR);
            if (curoff == (fpos_t)-1) {
                FUNLOCKFILE(fp);
                return (EOF);
            }
        }
        if (fp->_flags & __SRD) {
            curoff -= fp->_r;
            if (HASUB(fp))
                curoff -= fp->_ur;
        } else if (fp->_flags & __SWR && fp->_p != NULL)
            curoff += fp->_p - fp->_bf._base;

        offset += curoff;
        whence = SEEK_SET;
        havepos = 1;
        break;

    case SEEK_SET:
    case SEEK_END:
        curoff = 0;        /* XXX just to keep gcc quiet */
        havepos = 0;
        break;

    default:
        FUNLOCKFILE(fp);
        errno = EINVAL;
        return (EOF);
    }

    /*
     * Can only optimise if:
     *    reading (and not reading-and-writing);
     *    not unbuffered; and
     *    this is a `regular' Unix file (and hence seekfn==__sseek).
     * We must check __NBF first, because it is possible to have __NBF
     * and __SOPT both set.
     */
    if (fp->_bf._base == NULL)
        __smakebuf(fp);
    if (fp->_flags & (__SWR | __SRW | __SNBF | __SNPT))
    {
        errno = EBADF;
        goto dumb;
    }
    if ((fp->_flags & __SOPT) == 0) {
        if (seekfn != __sseek){
            fp->_flags |=  __SNPT;
            errno = ESPIPE;
            goto dumb;
        }
        if(fp->_file<0){
            fp->_flags |=  __SNPT;
            errno = EBADF;
            goto dumb;
        }
        if(fstat(fp->_file,&st)){
            fp->_flags |=  __SNPT;
            errno = EBADF;
            goto dumb;
        }
        if((st.st_mode & S_IFMT) != S_IFREG){
            fp->_flags |=  __SNPT;
            errno = ESPIPE;
            goto dumb;
        }
        fp->_blksize = st.st_blksize;
        fp->_flags |= __SOPT;
    }

    /*
     * We are reading; we can try to optimise.
     * Figure out where we are going and where we are now.
     */
    if (whence == SEEK_SET)
        target = offset;
    else {
        if (fstat(fp->_file, &st))
            goto dumb;
        target = st.st_size + offset;
    }

    if (!havepos) {
        if (fp->_flags & __SOFF)
            curoff = fp->_offset;
        else {
            curoff = (*seekfn)(fp->_cookie, (fpos_t)0, SEEK_CUR);
            if (curoff == POS_ERR)
                goto dumb;
        }
        curoff -= fp->_r;
        if (HASUB(fp))
            curoff -= fp->_ur;
    }

    /*
     * Compute the number of bytes in the input buffer (pretending
     * that any ungetc() input has been discarded).  Adjust current
     * offset backwards by this count so that it represents the
     * file offset for the first byte in the current input buffer.
     */
    if (HASUB(fp)) {
        curoff += fp->_r;    /* kill off ungetc */
        n = fp->_up - fp->_bf._base;
        curoff -= n;
        n += fp->_ur;
    } else {
        n = fp->_p - fp->_bf._base;
        curoff -= n;
        n += fp->_r;
    }

    /*
     * If the target offset is within the current buffer,
     * simply adjust the pointers, clear EOF, undo ungetc(),
     * and return.  (If the buffer was modified, we have to
     * skip this; see fgetln.c.)
     */
    if ((fp->_flags & __SMOD) == 0 &&
        target >= curoff && target < (fpos_t)(curoff + n)) {
        int o = target - curoff;

        fp->_p = fp->_bf._base + o;
        fp->_r = n - o;
        if (HASUB(fp))
            FREEUB(fp);
        fp->_flags &= ~__SEOF;
        FUNLOCKFILE(fp);
        return (0);
    }

    /*
     * The place we want to get to is not within the current buffer,
     * but we can still be kind to the kernel copyout mechanism.
     * By aligning the file offset to a block boundary, we can let
     * the kernel use the VM hardware to map pages instead of
     * copying bytes laboriously.  Using a block boundary also
     * ensures that we only read one block, rather than two.
     */
    curoff = target & ~(fp->_blksize - 1); /*lint !e502*/
    if ((*seekfn)(fp->_cookie, curoff, SEEK_SET) == POS_ERR)
        goto dumb;
    fp->_r = 0;
    fp->_p = fp->_bf._base;
    if (HASUB(fp))
        FREEUB(fp);
    fp->_flags &= ~__SEOF;
    n = target - curoff;
    if (n) {
        if (__srefill(fp))
            goto dumb;
        if ((size_t)fp->_r < n)
        {
            errno = ESPIPE;
            goto dumb;
        }
        fp->_p += n;
        fp->_r -= n;
    }
    FUNLOCKFILE(fp);
    return (0);

    /*
     * We get here if we cannot optimise the seek ... just
     * do it.  Allow the seek function to change fp->_bf._base.
     */
dumb:
    if (__sflush(fp) ||
        (*seekfn)(fp->_cookie, (fpos_t)offset, whence) == POS_ERR) {
        FUNLOCKFILE(fp);
        return (EOF);
    }
    /* success: clear EOF indicator and discard ungetc() data */
    if (HASUB(fp))
        FREEUB(fp);
    fp->_p = fp->_bf._base;
    fp->_r = 0;
    /* fp->_w = 0; */    /* unnecessary (I think...) */
    fp->_flags &= ~__SEOF;
    FUNLOCKFILE(fp);
    return (0);
}
#ifdef LOSCFG_LLTSER
extern int gcov_file_seek(int i,int offset,int whence);
extern char* gcov_file_path(int i);
#endif

/*
 * fseek()'s offset is a long and sizeof(off_t) != sizeof(long) on all arches
 */
#if defined(__alpha__) && defined(__indr_reference)
__indr_reference(fseeko, fseek);
#else
int
fseek(FILE *fp, long offset, int whence)
{
    off_t off = offset;
#ifdef LOSCFG_LLTSER
    GCOV_FSEEK(fp,offset,whence);
#endif
    return(fseeko(fp, off, whence));
}
int     fseeko64(FILE *fp, off64_t offset, int whence)
{
        off_t off = offset;

    return(fseeko(fp, off, whence));
}
#endif
